Electromagnetic contactor



Sept. 22, 1959 Filed Oct. 20, 1955 S. D. HENDERSON, JR

ELECTROMAGNETIC CONTACTOR 5 Sheets-Sheet 1 Sept. 22, 1959 S. D. HENDERSON, JR

ELECTROMAGNETIC CONTACTOR Filed Oct. 20, 1955 5 Sheets-Sheet 2 Sept. 22, 1959 S. D. HENDERSON, JR

ELECTROMAGNETIC CONTACTOR Filed Oct. 20, 1955 5 Sheets-Sheet 3 43 INVENTOR Stanley D. Henderson,Jr.

BY WK, @WM

ATTORNEY Sept. 22, 1959 s. D. HENDERSON, JR v 2,905,870

ELECTROMAGNETIC CONTACTOR 5 Sheets-Sheet 4 Filed Oct. 20, 1955 v Fig.5.

$4 .11. J m ft L. r. IHII IV R Sept. 22, 1959 s. n. HENDERSON, JR 2,905,870

ELECTROMAGNETIC CONTACTOR Filed Oct. 20, 1955 I 5 Sheets-Sheet 5 United States Patent ELECTROMAGNETIC CONTACTOR Stanley D. Henderson, Jr., Amherst, N.Y., assignor to Westinghouse Electric Corporation, East Pittsburgh, P n, a corporation of Pennsylvania Application October 20, 1955, Serial No. 541,648

Claims. (Cl. 317-157) This invention relates to electromagnetic contactors and, more particularly, to latching mechanism for such contactors.

An object of the invention is to provide an electromagnetic contactor embodying means for mechanically latching the contactor in operated position.

Another object of the invention is to provide an electromagnetic contact embodying means for mechanically latching the contactor in the closed position with electromagnetic means for effecting opening of the contactors.

Another object of the invention is to providean electromagnetic contactor according to the preceding paragraphs with interlocking means for interlocking the operating electromagnet and the tripping magnet.

The invention both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description thereof when read in conjunction with the accompanying drawings.

In said drawings:

Figure 1 is a front elevational view of an electromagnetic contactor embodying the principles of the invention;

Fig. 2 is a side-elevational view partly in section showing the detailed structure of the contactor;

Fig. 3 is a side elevational view partly in section of the contactor showing the interlock switch;

Fig. 4 is an enlarged front elevational view of the latching mechanism;

Fig. 5 is an enlarged bottom view of the latching mechanism;

Fig. 6 is a sectional view taken along line VI--VI of Fig. 4 Showing the latch structure; and

Fig. 7 is a schematic view showing the interlock circuits for the eontactor and the latch device and showing the contactor in the open position.

The invention is illustrated as applied to a contactor of the type disclosed in Patent No. 2,550,110, issued April 24, 1951 to Delbert Ellis and assigned to the assignee of the instant invention.

Referring to Figs. 1 and. 2 of the drawings, the con tactor is provided with a base plate 11 adapted to be mounted on a panel or other suitable support. A stationary contact support 13 of insulating material is rigidly mounted on the base plate 11 and has spaced stationary contacts 15 and 17 rigidly secured thereto. The spaced stationary contacts are adapted to be bridged in the closed position of the contactor by a movable bridging contact 19 mounted in a U-shaped bracket 21 which is rigidly mounted on an insulating arm 23. A spring 25 compressed between the arm 23 and the bridging contact 19 biases the latter against the bight of the bracket 21. The arm 23 is rigidly secured to a channel-shaped mem ber 27 which is supported for pivotal movement about a stationary pivot at a point within a circle indicated by the reference numeral 29 (Fig. 2). The contacts are enclosed in an arc chute 31 mounted on the insulating contact support member 13. An armature 33 is pivotally mounted in the channel-shaped member 27 by means of ice a pivot 35 for limited movement relative to the member 27. An electromagnet indicated generally at 37 (Fig. 3) comprises an E-shaped magnet yoke 39 secured to a front plate 41 mounted on the base plate 11 by means of brackets 43 and 45. An energizing coil 47 surrounds the center leg 49 of the E-shaped magnet yoke 39 and is held in place by means of leaf springs 51 (only one being shown) supported on the bracket 43, there being a spring 51 disposed on each side of the magnet yoke.

A bearing member 53 (Fig. 2) mounted on the bracket 45 by means of screws 55 (only one being shown) has an angular portion 57 which forms a seat for an armature retrieving spring 59 compressed between the seat 57 and a member 61 on the channel-shaped member 27.

Energiz ation of the coil 47 causes the armature 33 to be attracted to the magnet yoke 39 moving the bridging contact 19 into engagement with the spaced stationary contacts 15-17. The movable asssemblage has a slight overtravel beyond the position where the contacts engage, which movement merely compresses the spring 25 thereby providing contact pressure. When the electromagnet 37 is deenergized, the spring 59 restores the armature 33 and the moving contact assemblage to the open position in which it is shown in Figs. 2 and 3.

The contactor is provided with an interlock switch indicated generally at 63 (Fig. 3) which is operated by a projection 67 (Fig. l) of the insulating arm 23. The switch 63 is of the type fully disclosed in Patent No. 2,583,139, issued January 22, 1953 to Delbert Ellis and assigned to the assignee of the present invention. For this reason, only a bn'ef description of the interlock switch is given herein. The switch 63 shown in Fig. 3 is mounted by means of screws 71 on the base 13 which supports the stationary contacts of the co-ntactor, and comprises a plunger 73 slidable in a top 75 of insulating material. A bridging contact member 77 is loosely mounted on the plunger 73 and is biased to the open position by a spring 79. Operation of the contactor to the closed position causes the projection 67 of the arm 23 to engage the plunger '73 and move the bridging contact 77 into engagement with spaced contact strips 81 and 83, contact pressure being provided by a spring 85 having one end attached to the plunger 73.

As fully disclosed in the hereinbefore referred to Patent No. 2,583,139, the bridging contact 77 may be reversed so the spring 79 biases the bridging contact to the closed position and operation of the plunger 73 when the contactor is operated to the closed position would then move the bridging contact to the open position.

In some applications it is desirable to close the contactor by momentary energization of the electromagnet from a remote point and to mechanically hold the moving contacts in the closed position. In order to mechanically hold the moving contact arm in the closed position so that the contactor will not open when the clectromagnet 37 is deenergized, there is provided a latch mechanism indicated generally by the reference numeral 87 (Figs. 1 and 2), which may readily be assembled on the base plate 11 of the contactor.

The latch mechanism 87 comprises a separate unit mounted on a base 89 (Figs. 1, 2 and 4) which is secured to the base plate 11 of the contactor by means of two screws 91, the base 89 being spaced from the base plate 11 by an offset portion 93 at the upper end and by a spacer 95 at the lower end. Mounted on the base 89 by means of screws 97 is an angular frame 99 upon which the parts of the latch mechanism are mounted. Secured to the frame 99 by means of a screw 101 (Figs. 5 and 6) is a core member 103 having a slot 105 therein in which is disposed a latch 107. The latch 107 is pivotally supported in the slot by means of a pin 109 and is biased in a counter-clockwise or latching direction by a aeoasvo spring pressed plunger 111. The plunger 111 is disposed for sliding movement in an opening 113 in the core member 103 and is biased toward the left (Fig. 6) by a spring 115 disposed in the opening 113 and compressed between the plunger 111 and a screw plug 117 threaded into the opening 113 at the opposite end thereof from the plunger. An energizing coil 114 surrounds and is supported on the core 103.

An armature support member 119 mounted on the frame 99 by screws 121 pivotally supports an armature 123 by means of spaced knife-edge pivots 125. The armature support member is provided with hook portions 127, one at each end, the ends of which extend into openings 124 in the ends of the armature 123 to retain the armature in place.

The armature 123 is biased to its unattracted position by a spring 131 connected under tension to the armature below the pivot point and to a spring stud 133. Mounted on the armature 123 by means of screws 135 is a latch plate 137 which, in the open position of the main contactor, is engaged by the latch portion 139 of the latch 107 to hold the armature 123 in its attracted position for a purpose to be described later.

Also supported on the armature 123 for movement therewith is a movable bridging contact member 141. The bridging contact member 141 is slidably mounted on the inner end of a rod 143 supported in the ends of a pair of spaced arms 145 which are secured to the armature 123, the free ends of the arms 145 adjacent the rod 143 being spaced apart by a spacer 147. The bridging contact member 141 is guided in its sliding movement on the rod 143 by a bracket 149 mounted on the arms 145 by means of the rod 143 and a nut 151 threaded on the inner end of the rod 143. A spring 153 coiled about the rod 143 and compressed between the bridging contact member 141 and the end of the bracket 149 biases the bridging contact member to closed position and provides contact pressure in the closed position.

Cooperating with the movable bridging contact member 141 is a pair of spaced stationary contacts 155 which are mounted on the ends of a pair of screws 157 which threadedly engage an insulating bracket 1S9 mounted by means of screws 161 on the frame 99. Tne screws 157 are locked in adjusted position by means of nuts 163 and the threaded portion of terminals 165. The terminals 165 are mounted on the screws 157 for connecting the contacts in an electric circuit. Terminals 167 (Fig. 4) are also provided for connecting the coil 114 of the latch device in the electrical circuit.

The switch 63 (Fig. 3), which is open in the open position of the contactors, is connected in series relation with the coil 114 (Figs. 4, 5 and 6) of the latch device 237, and the contacts 141-155 of the latch device are connected in series relation with the coil 47 (Fig. 3) of the contactor magnet 37 and are closed in the open position of the contactor.

Referring to Fig. 7 of the drawings, the contactor is closed by operation of the close switch C over the closed contacts 141155 of the latch device. In the open position of the contactor, the latch portion 139 (Figs. 5 and 6) of the latch 107 engages the latch bar 137 and holds the armature 123 in the closed or attracted position, thus holding the contacts 141-153 closed. When the contactor magnet 37 is energized and moves the channelshaped member 27 to close the contactor, an car 169 (Figs. 2, 4 and 5) on the channel-shaped member moves to the position indicated at 163a (Fig. 5) during which movement it engages the latch portion 139 of the latch 107 and moves it to the position indicated at 139a. This action releases the armature 123 of the latch device permitting the spring 131 to move the armature to a position where the latch bar 137 is positioned in the path of opening movement of the car 163, thus mechanically holding the channel-shaped member 27 and the contactor in the closed contact position.

In the closed position of the contactor, the latch device contacts 141155 are open preventing energization of the contactor magnet 37 and the interlock switch 63 (Figs. 3 and 7) is closed, setting up a circuit over which the coil 114 of the latch device 37 may be energized to efiect opening of the contactor.

Opening of the contactor is effected by operation of the manual opening switch 0 which energizes the coil 11-1 of the latching device 87 over the now closed inter: lock switch 63. Energization of the coil 114 attracts the armature 123 disengaging the latch bar 137 from the ear 169 of the channel-shaped member 27, permitting the spring 59 (Fig. 2) to open the contactor contacts. Energization of the latch device coil 114 and the resultant attraction of the armature 123 closes the contacts 141155, setting up the circuit over which the contactor magnet 37 may be again energized upon operation of the closing switch C to close the contactor. Opening movement of the channel-shaped member 27. (Fig. 3) and the projection 67 thereon permits the spring 79 to open the switch 63, thus preventing energization of the coil 114 of the latching device 87 in the open position of the contactor.

The invention provides an electromagnetic contactor operable by momentary energization of an electromagnet, the moving parts of the contactor being mechanically latched in the closed position by a suitable latch mechanism which is itself latched in the unlatched position in the open position of the contactor by a second latch, the second latch being engaged and actuated to unlatching position by movement of the armature means of the contactor to the closed position to permit the first latch to engage the contactor armature mechanism and hold the contactor closed. An electromagnet is provided in the latch mechanism to effect unlatching of the contactor and relatching of the main latch in unlatching position.

Having described the invention in accordance with the provisions of the patent statutes, it is to be understood that various changes and modifications may be made therein without departing from the spirit of the invention.

I claim as my invention:

1. An electromagnetic contactor comprising stationary and movable contacts, a switch arm pivoted between its ends and having said movable contact mounted on one end thereof at one side of the pivot for said switch arm, electromagnetic means including armature means mounted on the other end of said switch arm at the other side of the pivot for said switch arm operable to close and open said contacts, a latch mechanism comprising a main latch biased to latching position, a second latch normally engaging and restraining said main latch in unlatching position, an integral portion on said armature means when said armature means is moved to close said contactor engaging and positively moving said second latch to unlatching position to permit said main latch to move to latching position where it restrains said armature and said contacts in closed position, and an electromagnet operable when energized to move said main latch to unlatching position thereby releasing said armature and permitting opening of said contacts.

2. An electromagnetic contactor comprising a base plate, stationary contacts, movable contacts biased to open position, a switch arm pivoted between its ends and having said movable contact mounted on one end thereof at one side of the pivot for said switch arm, electromagnetic means mounted on said base for operating said movable contacts to closed contact positions comprising armature means mounted on the other end of said switch arm at the other side of the pivot for said switch arm, a latching mechanism mounted as a unit on said base plate adjacent said electromagnetic means, said latching mechanism comprising a main latch biased to latching position, a second latch releasably restraining said main latch in unlatching position, a part integral with said armature means engaging and positively moving said second latch to unlatching position when said armature is moved to close said contacts to effect release of said main latch thereby permitting said main latch to move to a latching position where it engages said part integral with said armature means and restrains said movable contacts in closed position, and a tripping electromagnet operable when energized to move said main latch to said unlatching position permitting movement of said armature and said movable contacts to the open position.

3. In a contactor having normally open main contacts and electromagnetic means for closing said main contacts, a pivoted switch arm movable to close said main contacts, an auxiliary switch operated to closed position by said switch arm when said switch arm is moved to close said main contacts, a latch mechanism comprising a main latch, means biasing said main latch to a latching position, auxiliary contact means operated by said main latch, a second latch engaging and releasably holding said main latch in unlatching position and holding said auxiliary contact means in closed position, said switch arm when moved to close said main contacts engaging and positively moving said second latch to unlatching position to release said main latch, said biasing means upon release of said main latch moving said main latch to a position where it engages and releasably holds said switch arm in closed position and opens said auxiliary contacts, and a tripping electromagnet operable when energized to move said main latch to unlatching position to effect release of said switch arm and close said auxiliary contacts.

4. In a contactor having normally open main contacts and electromagnetic means for closing said main contacts, a pivoted switch arm movable to close said main contacts, an auxiliary switch operated to closed position by said switch arm when said switch arm is moved to close said main contacts, a latch mechanism comprising a main latch, means biasing said main latch to a latching position, auxiliary contact means operated by said main latch, a second latch engaging and releasably holding said main latch in unlatching position and holding said auxiliary contact means in closed position, means connecting said auxiliary contacts in series relation with said closing electromagnetic means permitting energization of said closing electromagnetic means only when said main latch is in unlatching position, said switch arm when moved to close said main contacts engaging and positively moving said second latch to unlatching position to release said main latch, said biasing means upon release of said main latch moving said main latch to a position where it engages and releasably holds said switch arm in closed position and opens said auxiliary contacts, a tripping electromagnet operable when energized to move said main latch to unlatohing position to effect release of said switch arm and close said auxiliary contacts, and means connecting said auxiliary switch in series relation with said tripping electromagnet permitting energization of said tripping electromagnet only when said main contacts are in the closed position.

5. In an electromagnetic contactor comprising a base plate, normally open contacts, electromagnetic means for closing said contacts, a switch arm biased to open position and movable to close said contacts, a latching device having a separate base member rigidly mounted on said base plate adjacent said switch arm, said latching device comprising an angular frame mounted on said base member, an armature pivotally supported on said frame and biased to unattracted position, main latch means on said armature, a tripping magnet comprising a fixed core member rigidly mounted on said angular frame and having a slot therein, a secondary latch pivotally supported on said fixed core member within said slot, said secondary latch normally engaging said armature and releasably holding said armature in attracted position and holding said main latch means in unlatching position, means on said switch arm engaging and positively moving said secondary latch when said switch arm is moved to close said contacts to eiTect release of said armature and said main latch means and permitting said main latch means to engage and releasably restrain said switch arm in closed position, and said tripping magnet when energized actuating said main latch means to efiect release of said switch arm and opening of said contacts.

References Cited in the file of this patent UNITED STATES PATENTS 2,448,470 Rypinski Aug. 31, 1948 2,459,349 Weber Jan. 18, 1949 2,535,366 Mead Dec. 26, 1950 2,607,867 Platz Aug. 19, 1952 2,618,693 Hay Nov. 18, 1952 

